A Non-Extensive Statistical Physics View of the Temporal Properties of the Recent Aftershock Sequences of Strong Earthquakes in Greece

Abstract

Greece is one of Europe’s most seismically active areas. Seismic activity in Greece has been characterized by a series of strong earthquakes with magnitudes up to Mw = 7.0 over the last five years. In this article we focus on these strong events, namely the Mw6.0 Arkalochori (27 September 2021), the Mw6.3 Elassona (3 March 2021), the Mw7.0 Samos (30 October 2020), the Mw5.1 Parnitha (19 July 2019), the Mw6.6 Zakynthos (25 October 2018), the Mw6.5 Kos (20 July 2017) and the Mw6.1 Mytilene (12 June 2017) earthquakes. Based on the probability distributions of interevent times between the successive aftershock events, we investigate the temporal evolution of their aftershock sequences. We use a statistical mechanics model developed in the framework of Non-Extensive Statistical Physics (NESP) to approach the observed distributions. NESP provides a strictly necessary generalization of Boltzmann–Gibbs statistical mechanics for complex systems with memory effects, (multi)fractal geometries, and long-range interactions. We show how the NESP applicable to the temporal evolution of recent aftershock sequences in Greece, as well as the existence of a crossover behavior from power-law (q ≠ 1) to exponential (q = 1) scaling for longer interevent times. The observed behavior is further discussed in terms of superstatistics. In this way a stochastic mechanism with memory effects that can produce the observed scaling behavior is demonstrated. To conclude, seismic activity in Greece presents a series of significant earthquakes over the last five years. We focus on strong earthquakes, and we study the temporal evolution of aftershock sequences of them using a statistical mechanics model. The non-extensive parameter q related with the interevent times distribution varies between 1.62 and 1.71, which suggests a system with about one degree of freedom.

Complexity of Recent Earthquake Swarms in Greece in Terms of Non-Extensive Statistical Physics

“…The cumulative inter-event time and distance distribution functions for each earthquake swarm are well described with the Q -exponential function, indicating asymptotic power–law behavior and long-term correlations in the spatiotemporal evolution of seismicity. In addition, the q -values of q T > 1 and q D < 1 are in agreement with the q -values found for aftershock sequences [ 38 , 40 , 83 , 93 , 94 ], for the Hellenic Subduction Zone [ 91 ], for the temporal properties of seismicity [ 60 , 61 ] and for global seismicity [ 41 , 84 ]. In addition, the concept of NESP describes well both the spatial and temporal behavior of the earthquake swarms in diverse tectonic environments [ 7 , 18 , 26 , 95 ] and in volcanic regions [ 23 , 59 ].…”

Kullback-Leibler Divergence(KLD) Formalism of The Stable Queue with KLD Applications to Biometrics

“…SI in a physical interpretation reads as "It does not matter whether one treats an independent subset of system states in terms of a separate conditional density or in terms of the full system density" (c.f., [24]).…”

Forecasting Strong Subsequent Earthquakes in Greece with the Machine Learning Algorithm NESTORE

“…Greece's location at the point of contact between the tectonic plates of Eurasia and Africa has resulted in several geodynamic processes and high seismicity, with multiple events of large magnitude recorded both in ancient and modern times. Greece ranks sixth in the world and first in the Mediterranean region for seismic energy emission [5,6]. The significant geotectonic phenomena, such as the continental convergence, where the oceanic crust of the North African plate is subducted under the European plate, are often associated in the literature with the high seismic activity in Greece.…”